/*
 * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
 *
 * HelenOS:
 * Copyright (c) 2012 Martin Sucha
 * Copyright (c) 2012 Frantisek Princ
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup lwext4
 * @{
 */
/**
 * @file  ext4_balloc.c
 * @brief Physical block allocator.
 */

#include <ext4_config.h>
#include <ext4_types.h>
#include <ext4_misc.h>
#include <ext4_errno.h>
#include <ext4_debug.h>

#include <ext4_trans.h>
#include <ext4_balloc.h>
#include <ext4_super.h>
#include <ext4_crc32.h>
#include <ext4_block_group.h>
#include <ext4_fs.h>
#include <ext4_bitmap.h>
#include <ext4_inode.h>

/**@brief Compute number of block group from block address.
 * @param s superblock pointer.
 * @param baddr Absolute address of block.
 * @return Block group index
 */
uint32_t ext4_balloc_get_bgid_of_block(struct ext4_sblock *s, uint64_t baddr) {
    if (ext4_get32(s, first_data_block) && baddr)
        baddr--;

    return (uint32_t)(baddr / ext4_get32(s, blocks_per_group));
}

/**@brief Compute the starting block address of a block group
 * @param s   superblock pointer.
 * @param bgid block group index
 * @return Block address
 */
uint64_t ext4_balloc_get_block_of_bgid(struct ext4_sblock *s, uint32_t bgid) {
    uint64_t baddr = 0;
    if (ext4_get32(s, first_data_block))
        baddr++;

    baddr += bgid * ext4_get32(s, blocks_per_group);
    return baddr;
}

#if CONFIG_META_CSUM_ENABLE
static uint32_t ext4_balloc_bitmap_csum(struct ext4_sblock *sb, void *bitmap) {
    uint32_t checksum = 0;
    if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
        uint32_t blocks_per_group = ext4_get32(sb, blocks_per_group);

        /* First calculate crc32 checksum against fs uuid */
        checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid, sizeof(sb->uuid));
        /* Then calculate crc32 checksum against block_group_desc */
        checksum = ext4_crc32c(checksum, bitmap, blocks_per_group / 8);
    }
    return checksum;
}
#else
#define ext4_balloc_bitmap_csum(...) 0
#endif

void ext4_balloc_set_bitmap_csum(struct ext4_sblock *sb, struct ext4_bgroup *bg,
                                 void *bitmap __unused) {
    int desc_size = ext4_sb_get_desc_size(sb);
    uint32_t checksum = ext4_balloc_bitmap_csum(sb, bitmap);
    uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
             hi_checksum = to_le16(checksum >> 16);

    if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
        return;

    /* See if we need to assign a 32bit checksum */
    bg->block_bitmap_csum_lo = lo_checksum;
    if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
        bg->block_bitmap_csum_hi = hi_checksum;
}

#if CONFIG_META_CSUM_ENABLE
static bool ext4_balloc_verify_bitmap_csum(struct ext4_sblock *sb,
                                           struct ext4_bgroup *bg,
                                           void *bitmap __unused) {
    int desc_size = ext4_sb_get_desc_size(sb);
    uint32_t checksum = ext4_balloc_bitmap_csum(sb, bitmap);
    uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
             hi_checksum = to_le16(checksum >> 16);

    if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
        return true;

    if (bg->block_bitmap_csum_lo != lo_checksum)
        return false;

    if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
        if (bg->block_bitmap_csum_hi != hi_checksum)
            return false;

    return true;
}
#else
#define ext4_balloc_verify_bitmap_csum(...) true
#endif

int ext4_balloc_free_block(struct ext4_inode_ref *inode_ref,
                           ext4_fsblk_t baddr) {
    struct ext4_fs *fs = inode_ref->fs;
    struct ext4_sblock *sb = &fs->sb;

    uint32_t bg_id = ext4_balloc_get_bgid_of_block(sb, baddr);
    uint32_t index_in_group = ext4_fs_addr_to_idx_bg(sb, baddr);

    /* Load block group reference */
    struct ext4_block_group_ref bg_ref;
    int rc = ext4_fs_get_block_group_ref(fs, bg_id, &bg_ref);
    if (rc != EOK)
        return rc;

    struct ext4_bgroup *bg = bg_ref.block_group;

    /* Load block with bitmap */
    ext4_fsblk_t bitmap_block_addr = ext4_bg_get_block_bitmap(bg, sb);

    struct ext4_block bitmap_block;

    rc = ext4_trans_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
    if (rc != EOK) {
        ext4_fs_put_block_group_ref(&bg_ref);
        return rc;
    }

    if (!ext4_balloc_verify_bitmap_csum(sb, bg, bitmap_block.data)) {
        ext4_dbg(DEBUG_BALLOC,
                 DBG_WARN "Bitmap checksum failed."
                          "Group: %" PRIu32 "\n",
                 bg_ref.index);
    }

    /* Modify bitmap */
    ext4_bmap_bit_clr(bitmap_block.data, index_in_group);
    ext4_balloc_set_bitmap_csum(sb, bg, bitmap_block.data);
    ext4_trans_set_block_dirty(bitmap_block.buf);

    /* Release block with bitmap */
    rc = ext4_block_set(fs->bdev, &bitmap_block);
    if (rc != EOK) {
        /* Error in saving bitmap */
        ext4_fs_put_block_group_ref(&bg_ref);
        return rc;
    }

    uint32_t block_size = ext4_sb_get_block_size(sb);

    /* Update superblock free blocks count */
    uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
    sb_free_blocks++;
    ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);

    /* Update inode blocks count */
    uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
    ino_blocks -= block_size / EXT4_INODE_BLOCK_SIZE;
    ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
    inode_ref->dirty = true;

    /* Update block group free blocks count */
    uint32_t free_blocks = ext4_bg_get_free_blocks_count(bg, sb);
    free_blocks++;
    ext4_bg_set_free_blocks_count(bg, sb, free_blocks);

    bg_ref.dirty = true;

    rc = ext4_trans_try_revoke_block(fs->bdev, baddr);
    if (rc != EOK) {
        bg_ref.dirty = false;
        ext4_fs_put_block_group_ref(&bg_ref);
        return rc;
    }
    ext4_bcache_invalidate_lba(fs->bdev->bc, baddr, 1);
    /* Release block group reference */
    rc = ext4_fs_put_block_group_ref(&bg_ref);

    return rc;
}

int ext4_balloc_free_blocks(struct ext4_inode_ref *inode_ref,
                            ext4_fsblk_t first, uint32_t count) {
    int rc = EOK;
    uint32_t blk_cnt = count;
    ext4_fsblk_t start_block = first;
    struct ext4_fs *fs = inode_ref->fs;
    struct ext4_sblock *sb = &fs->sb;

    /* Compute indexes */
    uint32_t bg_first = ext4_balloc_get_bgid_of_block(sb, first);

    /* Compute indexes */
    uint32_t bg_last = ext4_balloc_get_bgid_of_block(sb, first + count - 1);

    if (!ext4_sb_feature_incom(sb, EXT4_FINCOM_FLEX_BG)) {
        /*It is not possible without flex_bg that blocks are continuous
         * and and last block belongs to other bg.*/
        if (bg_last != bg_first) {
            ext4_dbg(DEBUG_BALLOC,
                     DBG_WARN "FLEX_BG: disabled & "
                              "bg_last: %" PRIu32 " bg_first: %" PRIu32 "\n",
                     bg_last, bg_first);
        }
    }

    /* Load block group reference */
    struct ext4_block_group_ref bg_ref;
    while (bg_first <= bg_last) {

        rc = ext4_fs_get_block_group_ref(fs, bg_first, &bg_ref);
        if (rc != EOK)
            return rc;

        struct ext4_bgroup *bg = bg_ref.block_group;

        uint32_t idx_in_bg_first;
        idx_in_bg_first = ext4_fs_addr_to_idx_bg(sb, first);

        /* Load block with bitmap */
        ext4_fsblk_t bitmap_blk = ext4_bg_get_block_bitmap(bg, sb);

        struct ext4_block blk;
        rc = ext4_trans_block_get(fs->bdev, &blk, bitmap_blk);
        if (rc != EOK) {
            ext4_fs_put_block_group_ref(&bg_ref);
            return rc;
        }

        if (!ext4_balloc_verify_bitmap_csum(sb, bg, blk.data)) {
            ext4_dbg(DEBUG_BALLOC,
                     DBG_WARN "Bitmap checksum failed."
                              "Group: %" PRIu32 "\n",
                     bg_ref.index);
        }
        uint32_t free_cnt;
        free_cnt = ext4_sb_get_block_size(sb) * 8 - idx_in_bg_first;

        /*If last block, free only count blocks*/
        free_cnt = count > free_cnt ? free_cnt : count;

        /* Modify bitmap */
        ext4_bmap_bits_free(blk.data, idx_in_bg_first, free_cnt);
        ext4_balloc_set_bitmap_csum(sb, bg, blk.data);
        ext4_trans_set_block_dirty(blk.buf);

        count -= free_cnt;
        first += free_cnt;

        /* Release block with bitmap */
        rc = ext4_block_set(fs->bdev, &blk);
        if (rc != EOK) {
            ext4_fs_put_block_group_ref(&bg_ref);
            return rc;
        }

        uint32_t block_size = ext4_sb_get_block_size(sb);

        /* Update superblock free blocks count */
        uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
        sb_free_blocks += free_cnt;
        ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);

        /* Update inode blocks count */
        uint64_t ino_blocks;
        ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
        ino_blocks -= free_cnt * (block_size / EXT4_INODE_BLOCK_SIZE);
        ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
        inode_ref->dirty = true;

        /* Update block group free blocks count */
        uint32_t free_blocks;
        free_blocks = ext4_bg_get_free_blocks_count(bg, sb);
        free_blocks += free_cnt;
        ext4_bg_set_free_blocks_count(bg, sb, free_blocks);
        bg_ref.dirty = true;

        /* Release block group reference */
        rc = ext4_fs_put_block_group_ref(&bg_ref);
        if (rc != EOK)
            break;

        bg_first++;
    }

    uint32_t i;
    for (i = 0; i < blk_cnt; i++) {
        rc = ext4_trans_try_revoke_block(fs->bdev, start_block + i);
        if (rc != EOK)
            return rc;
    }

    ext4_bcache_invalidate_lba(fs->bdev->bc, start_block, blk_cnt);
    /*All blocks should be released*/
    ext4_assert(count == 0);

    return rc;
}

int ext4_balloc_alloc_block(struct ext4_inode_ref *inode_ref, ext4_fsblk_t goal,
                            ext4_fsblk_t *fblock) {
    ext4_fsblk_t alloc = 0;
    ext4_fsblk_t bmp_blk_adr;
    uint32_t rel_blk_idx = 0;
    uint64_t free_blocks;
    int r;
    struct ext4_sblock *sb = &inode_ref->fs->sb;

    /* Load block group number for goal and relative index */
    uint32_t bg_id = ext4_balloc_get_bgid_of_block(sb, goal);
    uint32_t idx_in_bg = ext4_fs_addr_to_idx_bg(sb, goal);

    struct ext4_block b;
    struct ext4_block_group_ref bg_ref;

    /* Load block group reference */
    r = ext4_fs_get_block_group_ref(inode_ref->fs, bg_id, &bg_ref);
    if (r != EOK)
        return r;

    struct ext4_bgroup *bg = bg_ref.block_group;

    free_blocks = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
    if (free_blocks == 0) {
        /* This group has no free blocks */
        goto goal_failed;
    }

    /* Compute indexes */
    ext4_fsblk_t first_in_bg;
    first_in_bg = ext4_balloc_get_block_of_bgid(sb, bg_ref.index);

    uint32_t first_in_bg_index;
    first_in_bg_index = ext4_fs_addr_to_idx_bg(sb, first_in_bg);

    if (idx_in_bg < first_in_bg_index)
        idx_in_bg = first_in_bg_index;

    /* Load block with bitmap */
    bmp_blk_adr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);

    r = ext4_trans_block_get(inode_ref->fs->bdev, &b, bmp_blk_adr);
    if (r != EOK) {
        ext4_fs_put_block_group_ref(&bg_ref);
        return r;
    }

    if (!ext4_balloc_verify_bitmap_csum(sb, bg, b.data)) {
        ext4_dbg(DEBUG_BALLOC,
                 DBG_WARN "Bitmap checksum failed."
                          "Group: %" PRIu32 "\n",
                 bg_ref.index);
    }

    /* Check if goal is free */
    if (ext4_bmap_is_bit_clr(b.data, idx_in_bg)) {
        ext4_bmap_bit_set(b.data, idx_in_bg);
        ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group, b.data);
        ext4_trans_set_block_dirty(b.buf);
        r = ext4_block_set(inode_ref->fs->bdev, &b);
        if (r != EOK) {
            ext4_fs_put_block_group_ref(&bg_ref);
            return r;
        }

        alloc = ext4_fs_bg_idx_to_addr(sb, idx_in_bg, bg_id);
        goto success;
    }

    uint32_t blk_in_bg = ext4_blocks_in_group_cnt(sb, bg_id);

    uint32_t end_idx = (idx_in_bg + 63) & ~63;
    if (end_idx > blk_in_bg)
        end_idx = blk_in_bg;

    /* Try to find free block near to goal */
    uint32_t tmp_idx;
    for (tmp_idx = idx_in_bg + 1; tmp_idx < end_idx; ++tmp_idx) {
        if (ext4_bmap_is_bit_clr(b.data, tmp_idx)) {
            ext4_bmap_bit_set(b.data, tmp_idx);

            ext4_balloc_set_bitmap_csum(sb, bg, b.data);
            ext4_trans_set_block_dirty(b.buf);
            r = ext4_block_set(inode_ref->fs->bdev, &b);
            if (r != EOK) {
                ext4_fs_put_block_group_ref(&bg_ref);
                return r;
            }

            alloc = ext4_fs_bg_idx_to_addr(sb, tmp_idx, bg_id);
            goto success;
        }
    }

    /* Find free bit in bitmap */
    r = ext4_bmap_bit_find_clr(b.data, idx_in_bg, blk_in_bg, &rel_blk_idx);
    if (r == EOK) {
        ext4_bmap_bit_set(b.data, rel_blk_idx);
        ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group, b.data);
        ext4_trans_set_block_dirty(b.buf);
        r = ext4_block_set(inode_ref->fs->bdev, &b);
        if (r != EOK) {
            ext4_fs_put_block_group_ref(&bg_ref);
            return r;
        }

        alloc = ext4_fs_bg_idx_to_addr(sb, rel_blk_idx, bg_id);
        goto success;
    }

    /* No free block found yet */
    r = ext4_block_set(inode_ref->fs->bdev, &b);
    if (r != EOK) {
        ext4_fs_put_block_group_ref(&bg_ref);
        return r;
    }

goal_failed:

    r = ext4_fs_put_block_group_ref(&bg_ref);
    if (r != EOK)
        return r;

    /* Try other block groups */
    uint32_t block_group_count = ext4_block_group_cnt(sb);
    uint32_t bgid = (bg_id + 1) % block_group_count;
    uint32_t count = block_group_count;

    while (count > 0) {
        r = ext4_fs_get_block_group_ref(inode_ref->fs, bgid, &bg_ref);
        if (r != EOK)
            return r;

        struct ext4_bgroup *bg = bg_ref.block_group;
        free_blocks = ext4_bg_get_free_blocks_count(bg, sb);
        if (free_blocks == 0) {
            /* This group has no free blocks */
            goto next_group;
        }

        /* Load block with bitmap */
        bmp_blk_adr = ext4_bg_get_block_bitmap(bg, sb);
        r = ext4_trans_block_get(inode_ref->fs->bdev, &b, bmp_blk_adr);
        if (r != EOK) {
            ext4_fs_put_block_group_ref(&bg_ref);
            return r;
        }

        if (!ext4_balloc_verify_bitmap_csum(sb, bg, b.data)) {
            ext4_dbg(DEBUG_BALLOC,
                     DBG_WARN "Bitmap checksum failed."
                              "Group: %" PRIu32 "\n",
                     bg_ref.index);
        }

        /* Compute indexes */
        first_in_bg = ext4_balloc_get_block_of_bgid(sb, bgid);
        idx_in_bg = ext4_fs_addr_to_idx_bg(sb, first_in_bg);
        blk_in_bg = ext4_blocks_in_group_cnt(sb, bgid);
        first_in_bg_index = ext4_fs_addr_to_idx_bg(sb, first_in_bg);

        if (idx_in_bg < first_in_bg_index)
            idx_in_bg = first_in_bg_index;

        r = ext4_bmap_bit_find_clr(b.data, idx_in_bg, blk_in_bg, &rel_blk_idx);
        if (r == EOK) {
            ext4_bmap_bit_set(b.data, rel_blk_idx);
            ext4_balloc_set_bitmap_csum(sb, bg, b.data);
            ext4_trans_set_block_dirty(b.buf);
            r = ext4_block_set(inode_ref->fs->bdev, &b);
            if (r != EOK) {
                ext4_fs_put_block_group_ref(&bg_ref);
                return r;
            }

            alloc = ext4_fs_bg_idx_to_addr(sb, rel_blk_idx, bgid);
            goto success;
        }

        r = ext4_block_set(inode_ref->fs->bdev, &b);
        if (r != EOK) {
            ext4_fs_put_block_group_ref(&bg_ref);
            return r;
        }

    next_group:
        r = ext4_fs_put_block_group_ref(&bg_ref);
        if (r != EOK) {
            return r;
        }

        /* Goto next group */
        bgid = (bgid + 1) % block_group_count;
        count--;
    }

    return ENOSPC;

success:
    /* Empty command - because of syntax */
    ;

    uint32_t block_size = ext4_sb_get_block_size(sb);

    /* Update superblock free blocks count */
    uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
    sb_free_blocks--;
    ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);

    /* Update inode blocks (different block size!) count */
    uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
    ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
    ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
    inode_ref->dirty = true;

    /* Update block group free blocks count */

    uint32_t fb_cnt = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
    fb_cnt--;
    ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, fb_cnt);

    bg_ref.dirty = true;
    r = ext4_fs_put_block_group_ref(&bg_ref);

    *fblock = alloc;
    return r;
}

int ext4_balloc_try_alloc_block(struct ext4_inode_ref *inode_ref,
                                ext4_fsblk_t baddr, bool *free) {
    int rc;

    struct ext4_fs *fs = inode_ref->fs;
    struct ext4_sblock *sb = &fs->sb;

    /* Compute indexes */
    uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
    uint32_t index_in_group = ext4_fs_addr_to_idx_bg(sb, baddr);

    /* Load block group reference */
    struct ext4_block_group_ref bg_ref;
    rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
    if (rc != EOK)
        return rc;

    /* Load block with bitmap */
    ext4_fsblk_t bmp_blk_addr;
    bmp_blk_addr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);

    struct ext4_block b;
    rc = ext4_trans_block_get(fs->bdev, &b, bmp_blk_addr);
    if (rc != EOK) {
        ext4_fs_put_block_group_ref(&bg_ref);
        return rc;
    }

    if (!ext4_balloc_verify_bitmap_csum(sb, bg_ref.block_group, b.data)) {
        ext4_dbg(DEBUG_BALLOC,
                 DBG_WARN "Bitmap checksum failed."
                          "Group: %" PRIu32 "\n",
                 bg_ref.index);
    }

    /* Check if block is free */
    *free = ext4_bmap_is_bit_clr(b.data, index_in_group);

    /* Allocate block if possible */
    if (*free) {
        ext4_bmap_bit_set(b.data, index_in_group);
        ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group, b.data);
        ext4_trans_set_block_dirty(b.buf);
    }

    /* Release block with bitmap */
    rc = ext4_block_set(fs->bdev, &b);
    if (rc != EOK) {
        /* Error in saving bitmap */
        ext4_fs_put_block_group_ref(&bg_ref);
        return rc;
    }

    /* If block is not free, return */
    if (!(*free))
        goto terminate;

    uint32_t block_size = ext4_sb_get_block_size(sb);

    /* Update superblock free blocks count */
    uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
    sb_free_blocks--;
    ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);

    /* Update inode blocks count */
    uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
    ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
    ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
    inode_ref->dirty = true;

    /* Update block group free blocks count */
    uint32_t fb_cnt = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
    fb_cnt--;
    ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, fb_cnt);

    bg_ref.dirty = true;

terminate:
    return ext4_fs_put_block_group_ref(&bg_ref);
}

/**
 * @}
 */
